Abstract: A kind of block for building wall and the wall built with said blocks. There are many analogous blocks laid to overlap and stagger with upper/nether block continuously in said wall. The block extends lengthways and comprises top surface (1), bottom surface (2) and two end surfaces (3); the cross section thereof on the whole is a converse trumpet shape; the top surface (1) has a mid ridge (4) higher than the two sides of the surface so as to form the left/right supporting slope (5); the top surface (1) and the bottom surface (2) are formed in this way: when a block overlap with a analogous block thereunder to form a wall, the left and right supporting slope (5) become a blocking structure to lock the two blocks neighbored up and down, the raised dimension of the mid ridge (4) can cut off space-time trochoid. This invention also provides the assistant blocks, which cooperate with said blocks when building wall.